1. Field of the Invention
The present invention relates to a battery receiving mechanism for a noise cancellation headphone and, in particular, relates to the battery receiving mechanism characterized by the structure of a battery lid.
2. Related Background of the Invention
There are various devices using a battery as the power supply. For example, an active noise cancellation headphone or an earmuff (hereinafter, the headphone or ear muff is referred to as the “headphone or the like”), which actively cancels out environmental noise so as to prevent a user from hearing the same, detects environmental noise with a microphone, outputs a noise signal, and drives a speaker unit with the use of a cancellation signal which is the noise signal whose phase has been inverted. Therefore, in the active noise cancellation type headphone or the like, a battery is used as the power supply for driving a noise canceling circuit, and a battery receiving portion and a lid covering this battery receiving portion are provided in either one of the right and left housings for the headphone or the like.
A user mounts the headphone or the like on his/her head and the headphone or the like moves with the movement of the user. Depending on the circumstances, the headphone or the like violently moves due to a violent movement of a user. Therefore, the battery receiving mechanism in the headphone or the like needs to stably hold the battery even if the headphone or the like violently moves and, in particular, the lid covering the battery receiving portion is required not to be removed even if the headphone or the like violently vibrates. On the other hand, preferably, the battery can be easily replaced.
An example of prior art related to the battery receiving mechanism in the headphone or the like include a battery lid described in Japanese Patent Laid-Open No. 2008-160796. In the battery lid described in Japanese Patent Laid-Open No. 2008-160796, a recessed part for receiving a battery is formed in the side part of an ear cup assembly of the headphone or the like, and this recessed part is enabled to slide between an open position to open the recessed part and a closed position to cover the recessed part. In an embodiment, there is described a battery lid, wherein a battery is attached and detached by circumferentially rotating, sliding, and moving the battery lid so as to protrude from the outer surface of the housing of the ear cup and wherein the recessed part is covered by circumferentially rotating, sliding, and moving the battery lid. The above-described rotating and sliding movement is performed in a plane parallel to the surface of the ear cup, thus, ensuring operability is reasonable.
The battery lid described in Japanese Patent Laid-Open No. 2008-160796 covers the side part of the ear cup assembly, more specifically the outer surface of the ear cup assembly, i.e., the almost whole side surface opposite to the ear pad mounting side. Accordingly, in handling the headphone or the like, hands accordingly touch the battery lid, and if a force to touch the battery lid is large and the direction of this force is the direction to open the battery receiving portion, then the battery lid unexpectedly opens the battery receiving portion and the battery may be removed. Although the rotating and sliding range of the battery lid is restricted to a certain range, an application of a large force to rotate the battery lid beyond the above-described sliding range might damage the battery lid. The battery lid described in Japanese Patent Laid-Open No. 2008-160796 also has a drawback that if the headphone or the like is dropped, the drop impact reaches the battery lid and the sliding mechanism for the battery lid causing, the battery lid and the sliding mechanism for the battery lid to likely be damaged. Moreover, because the battery receiving portion is configured to be opened and closed by sliding and moving the battery lid relative to the side part of the ear cup assembly, a guide structure for sliding and moving the battery lid, a stopper for restricting the sliding range to a certain range, or the like is required and thus the structure has a drawback of becoming complicated.